Tephra characterization and multi-disciplinary determination of Eruptive Source Parameters of a weak paroxysm at Mount Etna (Italy)

The near real-time determination of Eruptive Source Parameters (ESPs) is one of the main challenges of modern volcanology. Strategies are now being developed to refine quantitative measurements of erupted mass, total grain-size distribution and plume height from ground sampling and remote sensing methods. However, each method has its own limitations and, therefore, ESPs remain poorly constrained.Between 2011 and 2015, Etna volcano has produced 49 paroxysmal episodes characterized by the emission of fountain-fed tephra plumes whose heights reached up to 15 km (above sea level). In this work, we take advantage of the complementary set of remote sensing data available at Etna for assessing the quantification of ESPs and their associated uncertainties based on ground deposit sampling, Doppler radar data, visible imagery and satellite observations. In particular, we have considered the 10 April 2011 as a case study of the weakest paroxysms given that some of the strongest paroxysms have already been studied to develop and enhance remote sensing and monitoring strategies at Etna (e.g. 23 November 2013 and 3 December 2015). Satellite thermal infrared and weather radar observations for this weak paroxysm show tephra plume altitudes of 6 to 9 km (a.s.l.), in agreement with simulations with HYSPLIT model. &#160;The erupted mass determined with all these sensors show a large variability that reflects the sensibility of each method to different grain sizes (e.g. from blocks and lapilli seen by L-band radar to very fine ash seen by satellite thermal-infrared). Our multi-sensor strategy shed some lights on the importance of intercomparing data from various approaches and studying their applicability limits for near real-time quantification of ESPs and monitoring purposes at Etna.

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Examples of Multi-Sensor Determination of Eruptive Source Parameters of Explosive Events at Mount Etna

Remote Sensing ◽

10.3390/rs13112097 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2097

Author(s):

Valentin Freret-Lorgeril ◽

Costanza Bonadonna ◽

Stefano Corradini ◽

Franck Donnadieu ◽

Lorenzo Guerrieri ◽

...

Keyword(s):

Grain Size ◽

Size Distribution ◽

Real Time ◽

Grain Size Distribution ◽

Source Parameters ◽

Radar Data ◽

Mount Etna ◽

Infrared Sensors ◽

Paroxysmal Activity

Multi-sensor strategies are key to the real-time determination of eruptive source parameters (ESPs) of explosive eruptions necessary to forecast accurately both tephra dispersal and deposition. To explore the capacity of these strategies in various eruptive conditions, we analyze data acquired by two Doppler radars, ground- and satellite-based infrared sensors, one infrasound array, visible video-monitoring cameras as well as data from tephra-fallout deposits associated with a weak and a strong paroxysmal event at Mount Etna (Italy). We find that the different sensors provide complementary observations that should be critically analyzed and combined to provide comprehensive estimates of ESPs. First, all measurements of plume height agree during the strong paroxysmal activity considered, whereas some discrepancies are found for the weak paroxysm due to rapid plume and cloud dilution. Second, the event duration, key to convert the total erupted mass (TEM) in the mass eruption rate (MER) and vice versa, varies depending on the sensor used, providing information on different phases of the paroxysm (i.e., unsteady lava fountaining, lava fountain-fed tephra plume, waning phase associated with plume and cloud expansion in the atmosphere). As a result, TEM and MER derived from different sensors also correspond to the different phases of the paroxysms. Finally, satellite retrievals for grain-size can be combined with radar data to provide a first approximation of total grain-size distribution (TGSD) in near real-time. Such a TGSD shows a promising agreement with the TGSD derived from the combination of satellite data and whole deposit grain-size distribution (WDGSD).

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Historical seismogram reproductions for the source parameters determination of the 1902, Atushi (Kashgar) earthquake

Journal of Seismology ◽

10.1007/s10950-017-9683-z ◽

2017 ◽

Vol 21 (6) ◽

pp. 1577-1597 ◽

Cited By ~ 4

Author(s):

Galina Kulikova ◽

Frank Krüger

Keyword(s):

Source Parameters

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The use of parallel computing for the high-resolution determination of earthquake source parameters

Физика земли ◽

10.31857/s0002-33372019268-75 ◽

2019 ◽

pp. 68-75

Author(s):

A. S. Fomochkina ◽

V. G. Bukchin

Keyword(s):

Parallel Computing ◽

Focal Mechanism ◽

Source Parameters ◽

Nodal Plane ◽

Earthquake Parameters ◽

Earthquake Source Parameters ◽

Detailed Search ◽

High Degree ◽

Special Case

Alongside the determination of the focal mechanism and source depth of an earthquake by direct examination of their probable values on a grid in the parameter space, also the resolution of these determinations can be estimated. However, this approach requires considerable time in the case of a detailed search. A special case of a shallow earthquake whose one nodal plane is subhorizontal is an example of the sources that require the use of a detailed grid. For studying these events based on the records of the long-period surface waves, the grids with high degree of detail in the angles of the focal mechanism are required. We discuss the application of the methods of parallel computing for speeding up the calculations of earthquake parameters and present the results of studying the strongest aftershock of the Tohoku, Japan, earthquake by this approach.

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Determination of source parameters of small earthquakes from P-wave rise time

Bulletin of the Seismological Society of America ◽

10.1785/bssa0630020599 ◽

1973 ◽

Vol 63 (2) ◽

pp. 599-614 ◽

Cited By ~ 4

Author(s):

M. E. O'Neill ◽

J. H. Healy

Keyword(s):

Rise Time ◽

Source Parameters ◽

P Wave ◽

Simple Method ◽

Zero Crossing ◽

Basic Measurement ◽

Earthquake Source Parameters ◽

Short Period ◽

Stress Drops

abstract A simple method of estimating source dimensions and stress drops of small earthquakes is presented. The basic measurement is the time from the first break to the first zero crossing on short-period seismograms. Graphs relating these measurements to rise time as a function of Q and instrument response permit an estimate of earthquake source parameters without the calculation of spectra. Tests on data from Rangely, Colorado, and Hollister, California, indicate that the method gives reasonable results.

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Source parameter determination of local earthquakes in Korea using moment tensor inversion of single station data

Bulletin of the Seismological Society of America ◽

10.1785/bssa0890041077 ◽

1999 ◽

Vol 89 (4) ◽

pp. 1077-1082 ◽

Cited By ~ 1

Author(s):

So Gu Kim ◽

Nadeja Kraeva

Keyword(s):

Moment Tensor ◽

Source Parameters ◽

Moment Tensor Inversion ◽

P Wave ◽

Parameter Determination ◽

Reverse Fault ◽

3D Tomography ◽

Single Station ◽

Slip Event

Abstract The purpose of this investigation is to determine source parameters such as focal mechanism, seismic moment, moment magnitude, and source depth from recent small earthquakes in the Korcan Peninsula using broadband records of three-component single station. It is very important and worthwhile to use a three-component single station in Korea because for most Korean earthquakes it is not possible to read enough first motions of P-wave arrivals because of the poor coverage of the seismic network and the small size (ML 5.0 or less) of the events. Furthermore the recent installation of the very broadband seismic stations in Korea and use of a 3D tomography technique can enhance moment tensor inversion to determine the source parameters of small earthquakes (ML 5.0 or less) that occur at near-regional distances (Δ ≤ 500 km). The focal solution for the Youngwol earthquake of 13 December 1996 is found to be a right-lateral strike slip event with a NE strike, and the Kyongju earthquake of 25 June 1997 is found to be an oblique reverse fault with a slight component of left-lateral slip in the SE direction.

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The observation of different aerosols types in the Mount Etna environment and their relative and mutual impacts on local radiative balance

10.5194/egusphere-egu21-12380 ◽

2021 ◽

Author(s):

Pasquale Sellitto ◽

Giuseppe Salerno ◽

Simona Scollo ◽

Alcide Giorgio di Sarra ◽

Antonella Boselli ◽

...

Keyword(s):

Spatial Scales ◽

Source Parameters ◽

Mount Etna ◽

Volcanic Plume ◽

Dynamical Regime ◽

Radiative Balance ◽

Volcanic Aerosols ◽

Aerosol Types ◽

Lidar Observations

The EPL-RADIO (Etna Plume Lab - Radioactive Aerosols and other source parameters for better atmospheric Dispersion and Impact estimatiOns) and EPL-REFLECT (near-source estimations of Radiative EFfects of voLcanic aErosols for Climate and air quality sTudies) projects, funded by the EC Horizon2020 ENVRIplus and EUROVOLC Transnational Access to European Observatories programmes, aim to advance the understanding of Mount Etna as a persistent source of atmospheric aerosols and its impact on the&#160; radiative budget at proximal to regional spatial scales. Research was tackled by carrying out three campaigns in the summers of 2016, 2017 and 2019 to observe the volcanic plume produced by passive degassing, proximally and distally from the summit craters, using a wide array of remote sensing and in situ instruments. Diverse data are collected to explore the link of inner degassing mechanisms to the characterisation of near-source aerosol physicochemical properties and subsequent impacts on the atmosphere, environment and regional climate system.The results of the three campaigns have shown that the volcanic plume emitted by Mount Etna often mixes with aerosols of different origins generating a complex layered pattern. Frequent mineral dust transport events were observed by both LiDAR observations located at Serra La Nave (~7 km south-west from summit craters) and at a medium-term radiometric station, equipped with a Multi-Filter Rotating Shadowband Radiometer (MFRSR), and other instruments located at Milo (~10 km eastwards from the craters). LiDAR observations also allowed to study the coexistence of volcanic aerosols and biomass burning particles from local to more distal smoke plumes transports (like for the well-documented large fires from continental southern Italy in July 2017). In situ filter and optical particles counter measurements confirmed the presence of dust at Milo. The interaction/mixing among volcanic, wildfire, and dust aerosols occurs in an overall dynamical regime which appears to be dominated by sea breeze, which is strengthened by the presence of the dark volcanic lava flanks. Photolysis process also possibly play a role in determining the daily evolution of the aerosol plume.The sources of these different aerosol types are studied in detail using Lagrangian trajectories and meteorological data. Off-line radiative transfer calculations, using EPL-RADIO/REFLECT observations as input data, are used to estimate the relative radiative impact of the different aerosol types with respect to the background passive-degassing aerosols coming from Mount Etna.

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